The present invention relates to an electrode assembly and, more particularly, to a disposable leg plate electrode assembly which is most useful as part of a fetal monitoring system.
Fetal monitoring is a technique which has been used for many years, primarily when a mother is giving birth. The technique is accomplished by attaching one or more electrodes to the fetus. An additional electrode attached to the mother is used to establish a base or reference voltage for the fetal electrodes. The fetal electrodes, via leads passing through the birth canal, and the additional electrode are connected to a fetal monitoring device.
In order to avoid accidentally dislodging the fetal electrodes, past electrode assemblies used a metal base plate strapped to the mother's thigh. The plate carries a pair of insulated connectors which engage the leads passing through the birth canal and connecting to the fetal electrodes. A main cable electrically coupled to the metal base plate and to the connectors is used to link the electrode assembly to the fetal monitoring device. This attachment prevents disengagement of the fetal electrodes in the event that the mother moves relative to the fetal monitoring device.
Although the electrode assembly described above has had some success, it has several drawbacks. The most significant of these drawbacks is its expense: the cost of such devices normally is between $50 and $100. Moreover, although they may be reused, the devices represent a capital investment to a hospital or clinic which cannot be directly charged to the patient. The expense is increased because the plate devices become soiled during use and must be cleaned before being reused. In addition, a hospital or clinic would require numerous identical devices to assure availability during the cleaning process.
An attempt to produce an electrode assembly which can overcome these drawbacks is disclosed in U.S. Pat. No. 4,209,020 issued to Nielson. The Nielson assembly is disposable and less expensive than those devices described above. Nevertheless, it still has practical problems, the two most significant of which are: 1) the way in which the leads from the remote fetal electrodes are attached to the electrode assembly, and 2) the way in which the electrode assembly is attached to the patient.
Nielson uses spring clips to attach the fetal electrode leads to the assembly. These protruding clips complicate both the use of the assembly and its manufacture. As a general rule, of course, the more complicated the manufacturing procedure, the more expensive the item. Nielson also uses an adhesive to attach the assembly to the patient. An adhesive attachment on the patient's skin precludes easy adjustment of the assembly, is uncomfortable for the patient, and risks injury to the patient upon removal.
Thus, the objects of the present invention are to simplify the manufacturing procedure to minimize cost while meeting the patient's needs, especially comfort and the assurance of a continually functional device.